Backup is a primary operation to protect data from corruption or accidental deletion. Traditionally, backup is triggered by a backup policy. In the EMC® Networker® suite of backup products, for example, backup may be governed by a policy expressed as a Recovery Point Objective (RPO). In prior approaches, the RPO typically is a measure of the maximum time period in which data might be lost if there is a Major Incident affecting an information technology (IT) service—not a direct measure of how much data might be lost. But in today's world an application or data center can scale rapidly. Statically configured backup policies based on RPO possess the risks of not protecting a very high amount of data in scale out environment.
A new dynamic backup policy based on amount of data change is needed in today's scale out and elastic environments. This policy is based on the amount of unprotected data an IT-Service can afford to lose in case of disaster. Backup applications are programmed to find the amount of unprotected data in the environment and triggers backup when the amount of unprotected data exceeds the threshold. The policy can be configured for the whole application or different directories of an application. For example in SQL/Exchange either we can set a single threshold for the whole SQL/Exchange Server or separate threshold for each database or group of databases in the server. Similarly in Hypervisor environment the policy can be configured for complete data center or a subset of virtual machines.
This policies doesn't affect the performance of production environment as backup is performed from the snapshot of volume. The backup applications also supports dedicated node to perform backup from the snapshot. Thus this policy can be triggered during any point in the day without affecting production environment.